Single dose pharmacokinetics of florfenicol in Fenneropenaeus chinensis

The pharmacokinetics of intravenously , intramuscularly and orally administered florfenicol were determined in Fenneropenaeus chinensis.The study was performed at 19~22 ℃.A dose of 15mg/ kg body mass was administered either intravenously or intramuscularly. The oral dose was13.56 mg/kg body mass. At 8~10 time points, from 0.083 h to 24 h after administration, blood was sampled from 8 individual shrimps in each group. The plasma was assayed for florfenicol using an HPLC method. The pharmacokinetic modling of the results was performed using the computer program MCP-KP. Following the three administrations, the plasma concentration –time data of florfenicol were all best described by two-compartment open model. The important parameters of intravenous, intramuscular and oral administrations were listed. The volumes of distribution( Vβ)were 1.287,1.293,2.421 L/kg, the total body clearance(Cs)was 0.129,0.138,0.213 L/(h·kg), the elimination halflives ( t(1/2)β) were 5.91,7.57,8.01 h, the peak plasma concentrations(Cmax) were 6.970,6.396,2.772 mg/L,and were estimated to occur at 0.206,0.239,0.605 h (Tmax) following dosing. The bioavailabilities (F) of intramuscular and oral administrations were 90.20% and 97.58%.